Safety device for plants delivering inflammable liquids



May 22, 1923. 1,456,390

M. LUDWIG SAFETY DEVICE FOR PLANTS DELIVERING INFLAMMABLE LIQUIDS FiledAug. 31, 1921 I flak A 3Z4 w 04M WZMQL$46 q// 7 2 y Patented May 22,1923,

MAX LUDWIG, OF BERLIN-LICHTEBFELDE, GERMANY,

ASSIG-NOR. T0. MARTINI '&

H'U'NEKE MASGHINENBAU-AKTIEN-GESELLSCI-IAFT, 0F BERLIN, GERMANY, A

CORPORATION OF GERMANY.

Application filed August 31, 1921.

To all whom it may concern.

Be it known that I, MAX LUDWIG, a citizen of Germany, and resident ofBerlin- Lichterfelde, Germany, have invented certain new and usefulImprovements in Safety Devices for Plants Delivering InflammableLiquids, of which the following is a specification.

In certain plants for the storage and delivery of highly inflammableliquids, such as gasoline, the liquid has been forced to the place ofdischarge by the pressure of a pro tective gas which positively guardedagainst explosion and like dangers. In other plants, the suction systemhas been substituted for the pressure system, and in this case thepositive protective action is generally lost. In Letters Patent of theUnited States No. 1,004,287 a suction system has been described in whichthe positive protecting action is produced by artificial means. For thispurpose, the patentee without resorting to mechanical intermediateconnections, employs an emergency vent left purposely on the suctionside of the pump, which vent is kept closed by a liquid seal as long asthere is a supply of protective gas sufficient for the safety of theplant, whereas upon the failure of the supply of protective gas theliquid seal is destroyed and the pump rendered inactive.

The present invention relates to a further development of the principlelaid down in said patent, and has particular reference to plants inWhich the protective atmosphere consists, not of a non-oxidizing gas,such as carbonic acid gas or nitrogen, but of air saturated with vaporsof the inflammable liquid and containing a proportion of such vaporslarge enough to render the mixture or air and vapors non-explosive. Thisgas is preferably made by mixing air intimately with an excess of liquidand introducing the saturated mixture thus obtained, into the storagetank. According to my invention, this mixture on its way from thesaturator, is led through an intermediate container which serves both asa means for separating the excess liquid and as a. liquid seal for thepurposely provided vent in the suction conduit. As long as the saturatoris working properly, this liquid seal is maintained, because the liquidof said seal is constantly replenished by the continuous separation ofSerial No. 497,429.

rated; thus, after a certain lapse of time, the I liquid seal isdestroyed and the liquid-drawing action of the pump interrupted by theadmission of air to the suction conduit of the pump. Until this stoppageof the liquidpumping action occurs, however, the air will take up somevapors during its passage through the liquidg so that the gaseous mix?ture still contains sufiicient vapors or moisture to benon-explosive andto act as a protective gas.

Another feature of my invention consists in a suction Windchest towhich, leads the seal-containing by-pass connecting at times the suctionside of the pump with the upper portion or gas space of the storagetank. The end portion of this by-pass which extends into theintermediate container having the liquid seal, is utilized forindicating the level of the liquid in the storage tank. I thus providemeasuring or indicating device for :the amount of liquid contained inthe storage tank at anyparticular time. of this device is based on thefact thatthe height of the indicating column of liquid contained in thisby-pass varies in a predetermined manner with any change in the level ofthe liquid in the storage tank. Reference is to be had to theaccompanying drawing, which is a apparatus embodying my presentinvention.

The highly inflammable liquid is contained in the storage tank l fromwhich the liquid is drawn through a pipe 2 into a suction windchest 3,whence, by the action of a pump 4, such liquid is caused to flow to thepump through a suction pipe 5, and from the pump through a delivery pipe6 into the upper portion of a receptacle or saturator 7, the dischargeend of said pipe 6 being provided with a downwardly directed opening 8delivering a portion of the liquid into said receptacle and with adownwardly directed nozzle 9 delivering theremaining portion of theliquid into a. pipe 10. It

Will be understood that the upper end of the a very simple and efficientThe operation vertical section of an pipe 10 is open to the receptacle7, and at the time of filling this receptacle, the air displaced by theinfiowing liquid passes out through this pipe, while whenever thepressure in the receptacle 7 is below atmospheric pressure, as at thetime liquid is drawn oli from the receptacle 7 for instance by openingthe cock shown at its bottom, an inwardly-opening check valve 11 willautomatically admit air to said receptacle, in a volume corresponding tothat of the liquid withdrawn. A saturated mixture of air and vapors ofthe inflammable liquid 'is formed in the pipe 10, and this mixture,together with any excess of liquid, passes into an intermediatecontainer 12. The level of the liquid in this container is determined bythe overflow pipe 13 which forms a return connection leading to thetank 1. The depth to which the pipe 10 dips into the liquid in thecontainer 12, is indicated by Another pipe14, dipping into said liquidto the depth t leads from the container 12 adjacent to a scale orindicator 15 and into the suction windchest 3. With the upper portion ofthe container -12 is further connected a vent pipe 16, the communicationof said pipe with the container being controlled by a ball valve 17closing toward the container. The purpose of this pipe is to provide forthe escape of air from the storage tank 1 at the time the latter isbeing filled with liquid.

The jet of liquid injected by the nozzle 9 into the pipe 10 continuouslyduring the op eration of the pump 4 is finely atomized so that the airis not merely saturated with vapors of the liquid, but also laden withfine drops. At the same time the liquid discharged into the vessel 7through the opening 8 will cause the level of the liquid to rise in saidvessel, and since the valve 11 closes outwardly, the rising liquid willcoinpress the air (or air and vapors) in the upper portion of the vessel7, and this pressure will assist the downward flow of the stream ofliquid and air through the pipe 10, and enable this stream to overcomethe resistance due to the hydrostatic pressure of the column or depth ofliquid t without requiring the use of suction or of a partial vacuum inthe storage tank 1 thus offering a distinct advantage over priorarrangements inc-lud ing pumps and storage tanks, operating withsaturation of air, which prior arrangements required a partial vacuum,or pressure below atmospheric, to be maintained in the storage tank. Theprotective gas contained in the upper portion of the intermediatecontainer 12 passes to the upper portion of the storage tank 1 throughthe pipe 13.

The partial vacuum created in the windchest 3 by the suction of the pump4 causes the liquid in the storage tank 1. Every va riation in the levelof the liquid in the tank 1 causes a change in the pressure prevailingin the windchest 3, this pressure always corresponding to the verticaldistance between the level of the liquid in the windchest and the levelof the liquid in the storage tank. The height h of the liquid column inthe pipe 14 is therefore always equal to the vertical distance betweenthe levels oi the liquid in thetank 1 and wind chest 3 respectively. Thepipe 14 is preferably made partly of glass, in order that the level ofthe liquid therein may be visible. It will be noted that when thestorage tank 1 is full, the distance between the two liquid levels is atits minimum, as indicated at h, corresponding to the minimum drop of thepressure in the windchest 3 below atmospheric pressure; when the tank lis practically empty, the distance between the two liquid levels attainsits maximum, as indicated at H, corresponding to the maximum drop of thepressure in the windchest below atmospheric pressure. The differencebet-ween said maximum H and said minimum h is equal to the diameter D orto the inside height of the tank 1.

The pipe 14 rises to a suflicient level to prevent the liquid from beingsucked through said pipe into the windchest 3. As explained above, saidpipe under normal conditions dips into the liquid in the container 12,and is sealed thereby, so that no air can enter the pipe 14 and passinto the windchest 3, to cause a possible interruption in theliquid-drawing action of the pump 4. It

will be evident that the presence, in the containe-r 12, of a sufficientamount of liquid to cover and seal the end of the pipe 14 therein,depends on the proper intimate saturation of the air entering thereceptacle 7 through the inlet 11, with'the atomized liquid insuiiicient excess to replenish the amount of liquid in theintermediatecontainer 12. If'for any'reason, as on account of a cloggingof the nozzle 9, the regular and proper saturation of such air shouldfail, this obviously will stop the furnishing of an' excess of liquid tothe container 12. Since the liquid in said container is no longerreplenished under these abnormal conditions,

it will be evaporated very quickly by the unsaturatedair passing throughsuch liquid; during this passage, however, the air will take up somevapor or liquid, so that the gas passing to the tank 1 through the pipe'13 will contain some liquid in vaporized form. The liquid-drawingoperation of the pump 4 can then be continued for a while, as long asthe level of the liquid in the container 12 does not fall below the endof the pipe 14 therein. As soon as the liquid uncovers the said end ofthe pipe, the liquid seal is broken, and air will pass from the upperportion of the container 12 through the pipe 14 to the windchest 3, sothat atmospheric pressure, or a pressure close thereto, will prevail inthe said windchest, as well as in the upper portion of the tank 1, sincethere will then be an unobstructed communication between theupper-portions of said tank and of said windchest by way of the pipe 13,container 12, and pipe 14. The pressure in said portions being thusequalized, the liquid in the wind,

chest 3 Will tend to run back into the tank 1, through the pipe 2, andas soon as the liquid level falls but slightly in the windchest 3, itwill partly uncover the lower end of the pipe 5, so that the pump willno longer draw liquid alone, but a mixture of air and liquid, and almostimmediately (when the lower end of the pipe 5 is uncovered fully) airalone will be drawn into the pump, so that the pumping of liquid willstop automatically. Inasmuch as the pipe 10 clips into the liquid in thecontainer 12 deeper than the pipe 14, the air passing from thereceptacle 7 through the pipe 10 to the container 12, will be compelledto pass through a body of liquid, and take up vapors, on its way fromthe pipe 10 to the pipe 13 and to the tank 1, even after the level ofthe liquid in said container has fallen sufliciently to uncover thelower end of the pipe 14 and thus stop the liquid-feeding action of thepump 4. I thus insure a stoppage of such action before any air, unmixedwith liquid or vapor, can reach the tank 1. It will be understood thatif air, unmixed with liquid or vapors, were allowed to reach the tank 1,the proportion of air in the gaseous mixture contained in the upperportion. of the tank 1 would soon rise to such a point that the mixturewould become explosive, and this is avoided by my invention.

Various modifications may be made with out departing from the nature ofmy invention as set forth in the appended claims.-

I claim:

1. A device of the class described, compri ing a storage tank, a pumphaving a suction connection to said tank to draw liquid therefrom, asaturating receptacle connected with the delivery port of the pump andhaving an air inlet, an intermediate container connected with saidreceptacle to receive air and liquid therefrom and also connected withthe said tank, and a connection, normally sealed by the liquid in saidcontainer, to admit air to the suction connection of the pump and thusstop the liquid-drawing action of said pump, when the liquid-seal inlet,an'intcrmediate container connectedwith said receptacle to receive airand liquid therefrom and also connected with said tank, and aconnection, normally sealed by the liquid in said container, and leadingto said windchest, to admit air to the suction connection of the pumpand thus stop the liquid-drawing action of the pump, when theliquid-seal is broken. 1

8. A device of the class described, comprising a storage tank, a pumphaving a suction connection to said tank to draw liquid therefrom, asaturating receptacle connected with the delivery port of the pump andhaving an air inlet, an intermediate container connected with saidreceptacle to receive air and liquid therefrom and also connected withthe said tank, a pipe rising from the said container and normally sealedby the liquid therein, to admit air to the suction connection of thepump and thus stop the liquid-drawing action of said pump, when theliquid-seal is broken, and an indicator adjacent to said pipe, to showthe level of the liquid there in and in the storage tank.

4. A device of the class described, comprising a storage tank, awindchest connected therewith, a pump having a suction connection tosaid windchest normally below the level of the liquid therein, asaturating receptacle connected with the delivery port-of the pump andhaving an air with said receptacle to receive air and liquid therefromand also connected with said tank, a pipe rising from said container andnormally sealed by the liquid therein, and connected with said windchestto admit air to the suction connection of the pump and thus stop theliquid-drawing action of said pump, when the liquid-seal is broken, andan indicator adjacent to said pipe, to show the level of the'liquidtherein and in the storage tank.

5. A device of the class described, comprising a storage tank, a pumphaving a suction connection to draw liquid therefrom, a saturatingreceptacle provided with an air inlet and an air outlet, a delivery pi eleading from said pump to said receptafie and having an outlet todischarge a portion of the liquid into said receptacle and a nozzle todischarge another portion of the liquid into said air outlet, anintermediate container connected with the air outlet of inlet, anintermediate container connected said receptacle to receive air andliquid therefrom, and also connected with said tank, and a connection,normally sealed by the liquid in said container, to admit air to thesuction connection of the pump and thus stop the liquid-drawing actionof the pump when the liquid seal is broken.

6. A device of the class described, co1nprising a storage tank, a pumphaving a suction connection to said tank to draw liquid therefrom, asaturating receptacle connected with the delivery port of the pump andhaving an air inlet, an intermediate container having; an orertlowconnection to said tank, a pipe for conducting air and liquid from saidreceptacle to said container and dipping into the latter below the levelae-e90 of the overflow, and a by-pass connection, likewise dipping intosaid container below the level of the overflow, so as to be normallysealed by the liquid therein, but to ,a smaller depth than said pipe, sothat specification.

MAX LUDWIG,

